A concave mirror has a focal length of 40 cm. Determine the object position for which the resulting image is upright and 4 times the size of the object.

You want to form an image on a screen 10 m from a mirror. If the image is 7 times bigger than the object, what type of mirror do you need? What is the radius of curvature?

A telescope is constructed with two lenses separated by 25 cm. The focal length of the objective is 20 cm. The focal length of the eyepiece is 5.0 cm. If an object is 100 m away from the objective lens, where is the final image of the eyepiece? What is its magnification?

An object is 20 cm in front of a lens of focal length 9.5 cm. A second lens of focal length -30 cm is 15 cm behind the first lens. Find the location of the final image and its magnification.